The present invention relates to a roller screen having several rotatable transverse rollers in succession at a distance from each other. The invention relates especially to a roller screen intended for the screening of pellets to be sintered, in which the overflow is intended to be fed to the sintering furnace and the underflow is returned to the pelleting process.
Many smelting processes require that the material to be smelted is not too finely divided, and therefore a finely divided raw material, e.g. a concentrate, must first be pelleted and thereafter sintered to increase the strength of the pellets. The capacity of a sintering furnace is, however, dependent, for example, on the size of the pellets fed into it. For this reason a roller screen is usually fitted between the pelleting plate and the sintering furnace. The roller screen separates the smallest pellets from the sintering furnace feed and returns them to pelleting in order to increase their particle size and to increase the sintering furnace capacity. However, the capacity of the sintering furnace varies, so that it is not always capable of receiving all the overflow from the roller screen.
The object of the present invention is to provide a roller screen of an improved type, by means of which the overflow quantity can be regulated.